1. Field of the Invention
The present invention relates generally to fluid pumping equipment management. More specifically, the present invention relates to systems, apparatus, program product, and methods for ensuring linearity of down-hole pumping systems.
2. Description of the Related Art
An oil and gas reservoir is composed of porous and permeable rock such as limestone, sandstone, or clay which contains oil in its pores. The oil and gas stored in the reservoir is prevented from reaching the surface due to an impermeable rock such as, for example, basalt, granite, or shale. The oil and gas within the reservoir can exert a substantial amount of vertical pressure on the impermeable rock.
Portions of an oil and gas well can be extended through the non-permeable rock to access the oil and gas in the reservoir. The typical oil and gas well can be thought of as a hole in the ground in which a steel pipe called a casing is placed. The annular space between the casing and the formation rock is filled with cement ideally resulting in a smooth steel lined hole in the ground passing through the reservoir. The steel casing is generally fairly uniformly cylindrically shaped along most of the length of the casing, and even in areas where there is a significant bend toward horizontal, the steel casing is still fairly uniform around the circumference. The “hole” formed by a drill bit is not always so cylindrically or circumferentially shaped. This difference can cause deviations in the newly installed steel casing as it will tend to follow the contours of the drill hole, at least to some extent. This deviation from cylindrical (in the circumference) can result in a deflection in the down-hole pumping system assembly if the down-hole pumping system assembly is positioned in contact with any such significant deviations in the casing, which can result in a shortened lifespan and/or complete failure of the down-hole pumping system assembly.
In a process called completion, holes are generated in the casing at the reservoir depth allowing oil, gas, and other fluids to enter the well and another smaller pipe hanging from the surface wellhead is added that allows the oil and gas to be brought to the surface in a controlled manner.
In a new well, the reservoir pressure is often sufficient to cause the oil and gas rise to the surface under its own pressure. Later, as the pressure decreases, or in deeper wells, additional motivation such as, for example, that provided by a down-hole pumping system assembly, is necessary.
As the oil and gas is removed, the pressure of the oil and gas in the rock pores is reduced. This reduction in pressure results in increased vertical effective stress and reservoir compaction. As the reservoir compacts, very large forces are generated which deforms the casing and added completion hardware. This deformation in the casing, whether caused by removal of the oil and gas or through other means, can also result in a deflection in the down-hole pumping system assembly which can result in a shortened lifespan and/or complete failure of the down-hole pumping system assembly.
Removal of the down-hole pumping system assembly or repair or replacement due to damage or early failure caused by irregularities in the casing of the well can result in an interruption of the oil and gas well production, which can cost millions of dollars in lost revenue. As such, recognized by the inventors is the need for systems and methods for monitoring and managing/maintaining the linearity of the down-hole pumping system assembly.
Various technologies were examined to determine if alternative technologies existed to try to solve the problem recognized by the inventors. Neither of the existing alternative technologies were found to be sufficiently effective. Childers et al., Down Hole Fiber Optic Real-Time Casing Monitor, Industrial and Commercial Applications of Smart Structures Technologies 2007, Proc. of SPIE vol. 6527, 65270J (2007), incorporated herein by reference, for example, describes an application of optical fiber to perform down-hole measurements employed as part of a real-time compaction monitoring (RTCM) project being developed by the assignee of the subject invention. Particularly, Childers et al. describes a Real-Time Casing Imager (RTCI) System used to directly measure compaction induced the formation and damage to an oil and gas well casing. The RTCI System includes surface instrumentation unit (SIU), a lead-in cable attached with standard cable clamps, and an RTCI cable connected to either the surface of the casing or to the sand-screen after drilling a well but prior to completion of the well. The attachment of the lead-in cable to the casing is performed with control line clamps which are common in the industry. The attachment of the RTCI cable to the casing or sand-screen, however, must be rigid to allow efficient strain transfer, and thus, is typically attached with an industrial adhesive. Further, the RTCI cable has a spiral or helical configuration to reduce incidences of breakage by reducing sensitivity to hoop stresses. Such configuration, however, often results in a substantial reduction in sensitivity. Also, once deployed, the RTCI cable cannot be easily repaired if there is a breakage or some other form of damage. Accordingly, it is not expected that the RTCI system described in Childers et al. would provide sufficient sensitivity, durability, or longevity with respect to determining or managing the linearity/alignment of a down-hole pumping system assembly to a level capable of being provided by embodiments of the present invention.
Also for example, Smith, U.S. Pat. No. 6,888,124, describes utilizing a single fiber-optic cable embedded with a series of electrical wires within a stator of an electrical motor to detect overheating and/or vibrations when the associated pump is blocked or runs dry or when a bearing has worn out. Such configuration, however, would not be expected to provide sufficient sensitivity to detect static deviations within the down-hole pumping system without substantial modification. Further, as the cable is embedded with the electrical wires of the stator, even if the configuration could be modified to provide sufficient sensitivity to detect static deviations in the pump and/or motor of a down-hole pumping system assembly, such configuration would not be expected to allow the optical fiber to be readily removed, adjusted, modified, or repaired, and thus, would not be expected to provide the benefits provided by embodiments of the present invention.